A display system for a construction machine is known that, in forming a predetermined target shape with the work tool provided to the tip of the work device of the construction machine during excavation or embankment work, displays on a display screen the image of a surface forming part of a target shape (target surface) and the image of the work tool to clarify the positional relation between the two and thereby assist the excavation work.
Patent Document 1 discloses a display system that changes the scale of the display screen based on the vertical distance between the work tool (bucket) and the target surface to allow both the target surface and the work tool to be displayed on the display screen even if the vertical distance between the work tool and the target surface (target excavation surface) changes.
Patent Document 2 also discloses a display system that calculates the position of the upper boundary line indicative of the height of the upper end of the target surface in a cross section and the position of the lower boundary line indicative of the height of the lower end of the target surface in a cross section in displaying the construction machine (hydraulic excavator) and the target surface (surface to be displayed) on the display screen (guide screen). The system further determines the display range of the display screen based on the vertical positional relation between the upper or lower boundary line calculated and the position of the construction machine, thereby vertically moving the display position of the target surface on the display screen.